I am using Acrobat Reader DC and do not see the Password Protect tool. Is this something that should have come with this product or will I need to order a different one?
Reader cannot add password protection to a PDF, this requires Acrobat DC instead.
So there is a difference between Acrobat Reader DC and Acrobat DC?
Yes. The former is free and therefore very limited in its capabilities. It can basically only display PDF files and allows you to fill in form fields and add comments, not perform any other type of editing, unlike the paid-for Acrobat, which can create PDF files and edit them in multiple ways, such as apply a security policy to them.